Plasticizers are incorporated into a resin (usually a plastic or elastomer) to increase the flexibility, workability, or distensibility of the resin. The largest use of plasticizers is in the production of “plasticized” or flexible polyvinyl chloride (PVC) products. Typical uses of plasticized PVC include films, sheets, tubing, coated fabrics, wire and cable insulation and jacketing, toys, flooring materials such as vinyl sheet flooring or vinyl floor tiles, adhesives, sealants, inks, and medical products such as blood bags and tubing, and the like.
Other polymer systems that use small amounts of plasticizers include polyvinyl butyral, acrylic polymers, nylon, polyolefins, polyurethanes, and certain fluoroplastics. Plasticizers can also be used with rubber (although often these materials fall under the definition of extenders for rubber rather than plasticizers). A listing of the major plasticizers and their compatibilities with different polymer systems is provided in “Plasticizers,” A. D. Godwin, in Applied Polymer Science 21st Century, edited by C. D. Craver and C. E. Carraher, Elsevier (2000); pp. 157-175.
Commonly assigned U.S. Pat. No. 9,321,898, incorporated by reference, identified plasticized vinyl chloride formulations using non-phthalate aromatic ester plasticizer. Commonly assigned US 2014-0315021, incorporated by reference, identified various blends of commercially available plasticizers with non-phthalate aromatic ester plasticizers. However, it has been observed that the aromatic esters produced by the methods described in these references contain byproduct impurities, such as aldehydes, acetates and color body impurities, making the esters less desirable for some plasticizer applications.
A method for producing purified aromatic esters is therefore desired.